The present invention is directed to a gas turbine engine assembly of a type capable of operating at elevated temperatures. In particular, the present invention is directed to an assembly creating a single cooling circuit for thermally isolating the turbine housing from high temperatures that would otherwise adversely impact the delivery of cooling air/oil through the high temperature gas path to cool bearings, seals, nozzles and other engine components as well as maintaining the housing structural integrity.
Recent advances in turbine engine technology utilize ceramic combustor technology which can operate at temperatures exceeding even 2500 xc2x0 F. It is essential that some housings must be cooled effectively and efficiently. Cooling the engine components while maintaining and even increasing engine efficiency and power are possible by operating at such higher temperatures without compromising the system.
Typically, such high temperature gas turbine engines require many complex cooling circuits to isolate the housing from high temperature gases. Separate cooling circuits are often utilized to cool the gas path liner and air/oil passages extending through the struts as required for lubrication of bearings, seals, turbine blades and associated engine components.
To insure adequate cooling, engine assemblies currently may utilize a circular inner hub and outer housing or shroud joined by a number of radially-extending support struts passing through the hot gas flow path. The struts may have hollow core areas extending lengthwise through the core for delivering air/oil to cool the bearings, nozzles and other components. The design of such inner hubs may accommodate bearings and various seal arrangements, while the outer shroud supports other ancillaries. The separate cooling circuits required for such shroud and hub assemblies are complex and expensive to fabricate and maintain.
There clearly is a need for an apparatus capable of creating a single cooling circuit which is simply supported within the engine compartment and capable of successfully isolating the entire engine housing from the high temperatures created by the gas combustion process, thereby enabling the housing to deliver cooling air to the bearings, seals, nozzles and other engine components.
In one aspect of the present invention, an apparatus is disclosed for thermally isolating a turbine engine housing from high temperatures created by combustion gases flowing through the engine. The apparatus includes a floating liner assembly that may be positioned within the engine housing, with a plurality of openings extending through the baffles. An outer baffle assembly may surround the floating liner assembly, with a plurality of openings extending through the outer baffle assembly. An inner baffle assembly may be arranged within the floating liner assembly, with a plurality of openings extending through the inner baffle. The floating liner assembly, the outer baffle assembly and the inner baffle assembly may be arranged to form a single passageway for conveying a stream of compressed, cooling air against said floating liner to extract heat from said floating liner by both conduction and convection. The cooling air after extracting heat is then expelled into a stream of combustion gases flowing through turbine engine.
In another aspect of the invention, a system is disclosed for thermally isolating a gas turbine engine housing having an outer ring-shaped housing member and an inner hub attached by housing struts from high temperatures created by combustion gases flowing through the turbine engine. The system includes a floating liner assembly that may be disposed between the inner hub and the outer ring-shaped housing member and may further include a plurality of liner struts enclosing the housing struts, with a plurality of openings extending through the floating liner. An outer baffle assembly may surround the floating liner assembly, with a plurality of openings extending through portions of the outer baffle assembly. An inner baffle assembly may be disposed within the floating liner assembly, with a plurality of openings extending through portions the inner baffle. A continuous stream of pressurized air may enter the outer ring-shaped housing member and may flow through the openings in the outer baffle assembly. The air stream may be directed against the floating liner to collect heat from the floating liner and expel the heat to a stream of combustion gases flowing through the gas turbine engine.
In a yet further aspect of the present invention, an apparatus and system are disclosed for thermally isolating an outer ring-shaped housing member of gas turbine engine having a number of inlets and an inner hub attached the outer ring-shaped housing member by a plurality of separate housing struts, from high temperatures created by combustion gases flowing through the turbine engine. The apparatus and system may include a floating liner assembly disposed between the inner hub and the outer ring-shaped housing member. The floating ring may include separate, radially-disposed inner and outer ring-shaped members, with each ring-shaped member having a number of openings. This may form a cooling air passageway adjacent each of the floating liner ring-shaped inner and outer members. An outer baffle assembly may be formed of two similar, generally cylindrically-shaped members attached to one another and surrounding the floating liner outer ringshaped member, with a plurality of openings extending through each outer baffle member. An inner baffle assembly may be formed of two similar, generally cylindrically-shaped members arranged within the floating liner inner ring-shaped member, with a plurality of openings extending through each inner baffle member. A single, continuous air cooling circuit may extend through the outer ring-shaped housing member and may flow through the openings in the outer and inner baffle assemblies, impacting on each of the floating liner inner and outer ring-shaped members. The stream may collect heat from each of the floating liner inner and outer ring-shaped members and expel the heat to a stream of combustion gases flowing through the gas turbine engine
These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims.